Semiconductor wafers are manufactured by a highly complex manufacturing process that requires many manufacturing tools. A wafer can be transferred from one manufacturing tool to the other by an overhead hoist transport (OHT) system. A typical OHT system includes multiple OHT rails. The OHI rails include pairs of parallel conductors that are fed by alternating current (AC) signals. These AC signals generate magnetic fields that introduce errors in electron beam systems.
AC power supply systems also generate magnetic fields that introduce particle beam location errors.